I took the original spacing out to 44mm. That's about as far as I dared go. That is comparable to 1-3/4" (1.73") and it's playable now for me.

Edit to add: The sound is okay. I have a Yamaha CG110-CE that sounds better but it's also a deeper box and close to classical specs minus the electronics and cutaway. The NTX1200R is a thin box. It's not going to emulate the deeper boxes of classical guitars. You need to know this is a guitar for playing plugged.